Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752438AbcD2JuJ (ORCPT ); Fri, 29 Apr 2016 05:50:09 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:46958 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751814AbcD2JuG (ORCPT ); Fri, 29 Apr 2016 05:50:06 -0400 Date: Fri, 29 Apr 2016 11:50:02 +0200 From: Pavel Machek To: Sakari Ailus Cc: Hans Verkuil , pali.rohar@gmail.com, sre@kernel.org, kernel list , linux-arm-kernel , linux-omap@vger.kernel.org, tony@atomide.com, khilman@kernel.org, aaro.koskinen@iki.fi, ivo.g.dimitrov.75@gmail.com, patrikbachan@gmail.com, serge@hallyn.com, tuukkat76@gmail.com, mchehab@osg.samsung.com, linux-media@vger.kernel.org Subject: Re: v4l subdevs without big device was Re: drivers/media/i2c/adp1653.c: does not show as /dev/video* or v4l-subdev* Message-ID: <20160429095002.GA22743@amd> References: <20160428084546.GA9957@amd> <20160429071525.GA4823@amd> <57230DE7.3020701@xs4all.nl> <20160429075649.GG32125@valkosipuli.retiisi.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160429075649.GG32125@valkosipuli.retiisi.org.uk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3438 Lines: 91 Hi! > > > adp1653 registers itself as a subdev, but there's no device that > > > register it as its part. > > > > > > (ad5820 driver seems to have the same problem). > > > > > > Is there example "dummy" device I could use, for sole purpose of > > > having these devices appear in /dev? They are on i2c, so both can work > > > on their own. > > > > Ah, interesting. This was discussed a little bit during the Media Summit > > a few weeks back: > > > > http://linuxtv.org/news.php?entry=2016-04-20.mchehab > > > > See section 5: > > > > "5. DT Bindings for flash & lens controllers > > > > There are drivers that create their MC topology using the device tree information, > > which works great for entities that transport data, but how to detect entities > > that don’t transport data such as flash devices, focusers, etc.? How can those be > > deduced using the device tree? > > > > Sensor DT node add phandle to focus controller: add generic v4l binding properties > > to reference such devices." > > > > This wasn't a problem with the original N900 since that didn't use DT AFAIK and > > these devices were loaded explicitly through board code. > > But now you run into the same problem that I have. Actually... being able to do board-code solution for testing for now would be nice... > > > > The solution is that sensor devices have to provide phandles to those controller > > devices. And to do that you need to define bindings which is always the hard part. > > > > Look in Documentation/devicetree/bindings/media/video-interfaces.txt, section > > "Optional endpoint properties". > > > > Something like: > > > > controllers: an array of phandles to controller devices associated with this > > endpoint such as flash and lens controllers. > > > > Warning: I'm no DT expert, so this is just a first attempt. > > > > Platform drivers (omap3isp) will have to add these controller devices to the list > > of subdevs to load asynchronously. > > I seem to have patches I haven't had time to push back then: > > > That gitweb is a bit confused about its own address, but I figured it out. Let me check... pavel@amd:/data/l/linux-n900$ git fetch git://git.retiisi.org.uk/~sailus/linux.git leds-as3645a:leds-as3645a fatal: unable to connect to git.retiisi.org.uk: git.retiisi.org.uk: Name or service not known pavel@amd:/data/l/linux-n900$ git fetch git://salottisipuli.retiisi.org.uk/~sailus/linux.git leds-as3645a:leds-as3645a remote: Counting objects: 132, done. remote: Compressing objects: 100% (46/46), done. remote: Total 132 (delta 111), reused 107 (delta 86) Receiving objects: 100% (132/132), 22.80 KiB | 0 bytes/s, done. Resolving deltas: 100% (111/111), completed with 34 local objects. >From git://salottisipuli.retiisi.org.uk/~sailus/linux * [new branch] leds-as3645a -> leds-as3645a > This seems to be mostly in line with what has been discussed in the meeting, > except that the patches add a device specific property. Please ignore the > led patches in that tree for now (i.e. four patches on the top are the > relevant ones here). > I'm currently trying to apply them to v4.6, but am getting rather ugly rejects :-(. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html